Pests image: Emerald Ash Borer (EAB)


Emerald Ash Borer (EAB) is a non-native wood-boring beetle that attacks all native species of true ash trees of any size and age. It was first detected near Detroit, MI, and Windsor, ON, in 2002 and since spread to more than 30 states and 5 provinces. The larvae feed on the inner vascular tissues, cutting off water and nutrient flow to the canopy, while mature beetles feed on the leaves from June to August. The moving of infested material causes long distance spread, however, adult beetles can fly and spread locally. EAB has been rapidly spreading across the continent, killing up to 99% of ash trees in its wake.

Sign and Symptoms

Emerald Ash Borer (EAB) infested ash trees may not initially show signs or symptoms. Early treatment prior to damage occurring greatly increases ash survival rates. Signs of EAB damage include crown thinning, bark splits, trunk shoots, D-shaped exit holes, S-shaped galleries, and woodpecker feeding. It can take up to 2–3 years before these signs become visible. If EAB is found in your area, it's best to have a tree care professional assess the health of your tree before considering treatment options.


Ash Tree

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A common challenge with managing Emerald Ash Borer (EAB) is the uncertainty of when or where to target treatments, removals, and replacements. Another challenge is detecting EAB early before signs and symptoms are visible and too much damage has been done to the tree. 

In commercial forestry, management decisions are supported by pest population data. However in urban forestry, many municipalities lack pest population data (e.g., where is the pest and what are the population levels) when managing EAB. The collection of pest population data is a critical component of any insect management program. The information generated by these surveys provides managers, who are often faced with limited financial and human resources, with data that facilitates informed decisions for forest protection programs (e.g., when and where to start/stop treatments). For instance, to detect and monitor EAB populations, BioForest recommends the use of green prism traps.

There are three main reasons to consider using green prism traps:

1. Early detection: There is no known EAB infestation within  25 km (15 miles) of the municipality or EAB has been detected within 25 km (15 miles) but not yet within the municipality. Prism traps help detect EAB early in an infestation which improves treatment success rate.

2. Early detection and monitoring: EAB has been detected within the municipality in just a few areas in very low populations and the extent of the infestation is not yet known. Prism traps can help estimate the age of an infestation in an area and detect new areas of infestation as EAB spreads throughout a municipality.

3. On-going monitoring of population trends: EAB is established or has been detected throughout the municipality. EAB is not uniform across a municipality. Using prism traps throughout
an infestation helps identify low, moderate and high population areas which helps target treatments and removals.

Prism trap surveys are a great way to detect and monitor EAB, but there are other activities that can supplement the data gathered from a trapping program. Branch sampling is another EAB detection and management tool developed by the Canadian Forest Service.

Treatment of trees should begin once a reported infestation is within a 25 km (15 miles) radius. Contact one of our experienced Technical Specialists to guide you along the next steps required to implement a treatment strategy.

Emerald Ash Borer: Where have we been, Where are we going?

Emerald ash borer presentation begins around 39 min and 27 sec.

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Emerald Ash Borer (EAB) was detected in North America in 2002 in Detroit, Michigan and Windsor, Ontario. Since then, EAB has resulted in the death of millions of ash trees, many in the urban forest.

In commercial forestry, management decisions are supported by pest population data. However, in urban forestry many municipalities lack pe...

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